Polyurethane transparencies are well known for use in aircraft applications. They are used alone or in combination with other plastics or polymers such as acrylic or polycarbonate sheeting for aircraft windows and cockpit canopies. The polyurethanes are particularly useful in cockpit canopies for fighter aircraft because of their impact resistance. The properties of the polyurethanes, particularly, the scratch and mar resistance could be improved if they could be reinforced with a fibrous material, such as glass fibers. However, because of their diameters and difference in index of refraction compared to the polyurethane, the optical properties of the resultant composites would not be acceptable.